Techniques are described herein that are capable of providing source control of custom code in a backend-as-a-service (BaaS) module. For instance, the custom code may be automatically loaded dynamically (e.g., on-demand) in a runtime that is hosted by the BaaS module while the runtime is running to provide custom backend features that are defined by the custom code to an application in response to receipt of a request from the application. Source control of the custom code may be provided without providing source control of host code that defines the runtime.